Method and apparatus for transmitting and receiving reference signal for sidelink data in wireless communication system

ABSTRACT

The disclosure relates to a communication technique and a system for fusing a 5 th  generation (5G) communication system with Internet of Things (IoT) technology to support a higher data rate after a 4G system. The disclosure can be applied to intelligent services (e.g., a smart home, a smart building, a smart city, a smart car or a connected car, healthcare, digital education, retail, security- and safety-related services, or the like), based on 5G communication technology and IoT-related technology. The disclosure provides a method and an apparatus for assigning frequency and time resources for data transmission in a wireless communication system.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based on and claims priority under 35 U.S.C. §119(e) of a U.S. Provisional application Ser. No. 62/938,255, filed onNov. 20, 2019, in the U.S. Patent and Trademark Office, and of a U.S.Provisional application Ser. No. 62/938,898, filed on Nov. 21, 2019, inthe U.S. Patent and Trademark Office, the disclosure of each of which isincorporated by reference herein in its entirety.

BACKGROUND 1. Field

The disclosure relates to a wireless mobile communication system. Moreparticularly, the disclosure relates to a method and an apparatus forfinding a frequency-time resource to be transmitted and transmitting afrequency-time resource through which data is transmitted to a receivingterminal, that is, resource allocation, in a process in which a vehicleterminal supporting vehicle communication (vehicle-to-everything,hereinafter referred to as “V2X”) transmits and receives datainformation in communication between terminals, such as sidelinks withother vehicle terminals and pedestrian mobile terminals.

2. Description of Related Art

To meet the demand for wireless data traffic having increased sincedeployment of 4^(th) generation (4G) communication systems, efforts havebeen made to develop an improved 5^(th) generation (5G) or pre-5Gcommunication system. Therefore, the 5G or pre-5G communication systemis also called a “Beyond 4G Network” or a “Post LTE System”. The 5Gcommunication system defined by 3GPP is called a “New Radio (NR)system”.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission distance, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques have beendiscussed in 5G communication systems and applied to the NR system.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancellation and the like.

In the 5G system, hybrid FSK and QAM modulation (FQAM) and slidingwindow superposition coding (SWSC) as an advanced coding modulation(ACM), and filter bank multi carrier (FBMC), non-orthogonal multipleaccess (NOMA), and sparse code multiple access (SCMA) as an advancedaccess technology have also been developed.

The Internet, which is a human centered connectivity network wherehumans generate and consume information, is now evolving to the Internetof things (IoT) where distributed entities, such as things, exchange andprocess information without human intervention. The Internet ofeverything (IoE), which is a combination of the IoT technology and thebig data processing technology through connection with a cloud server,has emerged. As technology elements, such as “detection technology”,“wired/wireless communication and network infrastructure”, “serviceinterface technology”, and “security technology” have been demanded forIoT implementation, a sensor network, a machine-to-machine (M2M)communication, machine type communication (MTC), and so forth have beenrecently researched. Such an IoT environment may provide intelligentInternet technology services that create a new value to human life bycollecting and analyzing data generated among connected things. IoT maybe applied to a variety of fields including smart home, smart building,smart city, smart car or connected cars, smart grid, health care, smartappliances and advanced medical services through convergence andcombination between existing information technology (IT) and variousindustrial applications.

In line with this, various attempts have been made to apply 5Gcommunication systems to IoT networks. For example, technologies, suchas a sensor network, machine type communication (MTC), andmachine-to-machine (M2M) communication may be implemented bybeamforming, MIMO, and array antennas. Application of a cloud radioaccess network (RAN) as the above-described big data processingtechnology may also be considered an example of convergence of the 5Gtechnology with the IoT technology.

In line with development of communication systems, vehicle-to-everything(V2X) systems have been variously developed.

The above information is presented as background information only toassist with an understanding of the disclosure. No determination hasbeen made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the disclosure.

SUMMARY

Aspects of the disclosure are to address at least the above-mentionedproblems and/or disadvantages and to provide at least the advantagesdescribed below. Accordingly, an aspect of the disclosure is to providea wireless communication system and, more particularly, to a method andan apparatus for selecting a transmission resource in a process in whicha vehicle terminal supporting vehicle-to-everything (V2X) exchangesinformation with another vehicle terminal and a pedestrian mobileterminal by using a sidelink. Specifically, the disclosure relates to areference for selecting resources in connection with a case in which aterminal directly assigns a sidelink transmission resource throughdetection, and operations of a base station and a terminal regarding thesame. In addition, the disclosure provides a method and an apparatus fortransmitting and receiving a physical sidelink shared channeldemodulation reference signal (DMRS) for sidelink datatransmission/reception.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

In accordance with an aspect of the disclosure a method by a firstterminal for solving the above-mentioned problems is provided. Themethod by first terminal includes the steps of identifying the number ofsymbols for physical sidelink shared channel (PSSCH) transmission andthe number of symbols for PSSCH DMRS, transmitting, to a secondterminal, sidelink control information (SCI) for scheduling the PSSCHtransmission, the SCI including DMRS pattern information identifiedbased on the number of symbols for the PSSCH DMRS, and transmitting, tothe second terminal, the PSSCH DMRS at a position identified based onthe SCI. A symbol index of the position at which the PSSCH DMRS istransmitted is identified by one of a plurality of index groups includedin a first index group for the number of symbols of the PSSCH DMRS being2, a second index group for the number of symbols of the PSSCH DMRSbeing 3, and a third index group for the number of symbols of the PSSCHDMRS being 4. The first index group includes {1, 5}, {3, 8}, {3, 10},{4, 8}, and {4, 10}, the second index group includes {1, 4, 7}, {1, 5,9}, and {1, 6, 11}, and the third index group includes {1, 4, 7, 10}.

In accordance with another aspect of the disclosure a method by a secondterminal for solving the above-mentioned problems is provided. Themethod by second terminal includes the steps of receiving, from a firstterminal, SCI for scheduling PSSCH transmission, the SCI including DMRSpattern information identified based on the number of symbols for thePSSCH DMRS, identifying the number of symbols for the PSSCH transmissionand the number of symbols for the PSSCH DMRS, based on the SCI, andreceiving, from the first terminal, the PSSCH DMRS at a positionidentified based on the SCI. A symbol index of the position at which thePSSCH DMRS is received is identified by one of a plurality of indexgroups included in a first index group for the number of symbols of thePSSCH DMRS being 2, a second index group for the number of symbols ofthe PSSCH DMRS being 3, and a third index for when the number of symbolsof the PSSCH DMRS being 4. The first index group includes {1, 5}, {3,8}, {3, 10}, {4, 8}, and {4, 10}, the second index group includes {1, 4,7}, {1, 5, 9}, and {1, 6, 11}, and the third index group includes {1, 4,7, 10}.

In accordance with another aspect of the disclosure a first terminal forsolving the above-mentioned problems is provided. The first terminalincludes a transceiver configured to transmit and receive a signal, andat least one processor coupled to the transceiver. The at least oneprocessor is configured to identify the number of symbols for PSSCHtransmission and the number of symbols for PSSCH DMRS, transmit, to asecond terminal, SCI for scheduling the PSSCH transmission, the SCIincluding DMRS pattern information identified based on the number ofsymbols for the PSSCH DMRS, and transmit, to the second terminal, thePSSCH DMRS at a position identified based on the SCI. A symbol index ofthe position at which the PSSCH DMRS is transmitted is identified by oneof a plurality of index groups included in a first index group for thenumber of symbols of the PSSCH DMRS being 2, a second index group forthe number of symbols of the PSSCH DMRS being 3, and a third index groupfor the number of symbols of the PSSCH DMRS being 4. The first indexgroup includes {1, 5}, {3, 8}, {3, 10}, {4, 8}, and {4, 10}, the secondindex group includes {1, 4, 7}, {1, 5, 9}, and {1, 6, 11}, and the thirdindex group includes {1, 4, 7, 10}.

In accordance with another aspect of the disclosure second terminal forsolving the above-mentioned problems is provided. The second terminalincludes a transceiver configured to transmit and receive a signal, andat least one processor coupled to the transceiver. The at least oneprocessor is configured to receive, from a first terminal, SCI forscheduling PSSCH transmission, the SCI including DMRS patterninformation identified based on the number of symbols for the PSSCHDMRS, identify the number of symbols for the PSSCH transmission and thenumber of symbols for the PSSCH DMRS, based on the SCI, and receive,from the first terminal, the PSSCH DMRS at a position identified basedon the SCI. A symbol index of the position at which the PSSCH DMRS isreceived is identified by one of a plurality of index groups included ina first index group for the number of symbols of the PSSCH DMRS being 2,a second index group for the number of symbols of the PSSCH DMRS being3, and a third index group for the number of symbols of the PSSCH DMRSbeing 4. The first index group includes {1, 5}, {3, 8}, {3, 10}, {4, 8},and {4, 10}, the second index group includes {1, 4, 7}, {1, 5, 9}, and{1, 6, 11}, and the third index group includes {1, 4, 7, 10}.

The disclosure proposes a method for detection and resource allocationwhile minimizing power consumed by a terminal during sidelinkcommunication, and the method may be effectively used to optimize powerconsumption by the terminal. In addition, according to an embodiment ofthe disclosure, it becomes possible to efficiently transmit/receive aDRMS for sidelink data.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the disclosure will be more apparent from the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1A is a view illustrating a system according to an embodiment ofthe disclosure, FIG. 1B is a view illustrating a system according to anembodiment of the disclosure, FIG. 1C is a view illustrating a systemaccording to an embodiment of the disclosure, and FIG. 1D is a viewillustrating a system according to an embodiment of the disclosure;

FIG. 2A is a diagram illustrating a vehicle-to-everything (V2X)communication method performed through a sidelink according to anembodiment of the disclosure, and FIG. 2B is a diagram illustrating aV2X communication method performed through a sidelink according to anembodiment of the disclosure;

FIG. 3 is a diagram illustrating a resource pool defined as a set ofresources on a time and frequency used for transmission and reception ofa sidelink according to an embodiment of the disclosure;

FIG. 4 is a diagram illustrating a method for a base station to assigntransmission resources in a sidelink according to an embodiment of thedisclosure;

FIG. 5 is a diagram illustrating a method of directly assigning atransmission resource of a sidelink through sensing by a terminal in asidelink according to an embodiment of the disclosure;

FIG. 6 is a diagram illustrating a mapping structure of physicalchannels mapped to one slot in a sidelink according to an embodiment ofthe disclosure;

FIG. 7 is a diagram illustrating a method of selecting a resource andreselecting a resource by a terminal in Mode 2 according to anembodiment of the disclosure;

FIG. 8 is a diagram illustrating a process in which one transport blockis divided into several code blocks and a cyclic redundancy check (CRC)is added according to an embodiment of the disclosure;

FIGS. 9A, 9B and 9C are diagrams illustrating one, two, or threefrequency-time resources are assigned and indicated according to anembodiment of the disclosure;

FIGS. 10A, 10B, 10C, and 10D are diagrams illustrating a method ofdetermining demodulation reference signal (DMRS) time resourcesaccording to various embodiments of the disclosure;

FIGS. 11A, 11B, and 11C are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure;

FIGS. 12A, 12B, 12C, and 12D are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure;

FIGS. 13A, 13B, 13C, 13D, 13E, 13F, and 13G are diagrams illustrating amethod of determining DMRS time resources according to variousembodiments of the disclosure;

FIGS. 14A, 14B, 14C, 14D, and 14E are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure;

FIGS. 15A, 15B, 15C, and 15D are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure;

FIG. 16 is a diagram illustrating a method of determining DMRS timeresources according to an embodiment of the disclosure;

FIG. 17 is a diagram illustrating a structure of a terminal according toan embodiment of the disclosure; and

FIG. 18 is a diagram illustrating a structure of a base stationaccording to an embodiment of the disclosure.

The same reference numerals are used to represent the same elementsthroughout the drawings.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thedisclosure. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of thedisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of thedisclosure is provided for illustration purpose only and not for thepurpose of limiting the disclosure as defined by the appended claims andtheir equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

In describing embodiments of the disclosure, descriptions related totechnical contents well-known in the art and not associated directlywith the disclosure will be omitted. Such an omission of unnecessarydescriptions is intended to prevent obscuring of the main idea of thedisclosure and more clearly transfer the main idea.

For the same reason, in the accompanying drawings, some elements may beexaggerated, omitted, or schematically illustrated. Further, the size ofeach element does not completely reflect the actual size. In thedrawings, identical or corresponding elements are provided withidentical reference numerals.

The advantages and features of the disclosure and ways to achieve themwill be apparent by making reference to embodiments as described belowin conjunction with the accompanying drawings. However, the disclosureis not limited to the embodiments set forth below, but may beimplemented in various different forms. The following embodiments areprovided only to completely disclose the disclosure and inform thoseskilled in the art of the scope of the disclosure, and the disclosure isdefined only by the scope of the appended claims. Throughout thespecification, the same or like reference numerals designate the same orlike elements.

Here, it will be understood that each block of the flowchartillustrations, and combinations of blocks in the flowchartillustrations, can be implemented by computer program instructions.These computer program instructions can be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions specified in the flowchart block or blocks.These computer program instructions may also be stored in a computerusable or computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer usable orcomputer-readable memory produce an article of manufacture includinginstruction means that implement the function specified in the flowchartblock or blocks. The computer program instructions may also be loadedonto a computer or other programmable data processing apparatus to causea series of operational steps to be performed on the computer or otherprogrammable apparatus to produce a computer implemented process suchthat the instructions that execute on the computer or other programmableapparatus provide steps for implementing the functions specified in theflowchart block or blocks.

Further, each block of the flowchart illustrations may represent amodule, segment, or portion of code, which includes one or moreexecutable instructions for implementing the specified logicalfunction(s). It should also be noted that in some alternativeimplementations, the functions noted in the blocks may occur out of theorder. For example, two blocks shown in succession may in fact beexecuted substantially concurrently or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved.

As used herein, the “unit” refers to a software element or a hardwareelement, such as a Field Programmable Gate Array (FPGA) or anApplication Specific Integrated Circuit (ASIC), which performs apredetermined function. However, the “unit” does not always have ameaning limited to software or hardware. The “unit” may be constructedeither to be stored in an addressable storage medium or to execute oneor more processors. Therefore, the “unit” includes, for example,software elements, object-oriented software elements, class elements ortask elements, processes, functions, properties, procedures,sub-routines, segments of a program code, drivers, firmware,micro-codes, circuits, data, database, data structures, tables, arrays,and parameters. The elements and functions provided by the “unit” may beeither combined into a smaller number of elements, or a “unit”, ordivided into a larger number of elements, or a “unit”. Moreover, theelements and “units” or may be implemented to reproduce one or morecentral processing units (CPUs) within a device or a security multimediacard. Further, the “unit” in the embodiments may include one or moreprocessors.

The following detailed description of embodiments of the disclosure isdirected to New RAN (NR) as a radio access network and packet core as acore network (5^(th) generation (5G) system, 5G Core Network, or newgeneration core (NG Core)) which are specified in the 5G mobilecommunication standards defined by the 3rd generation partnershipproject long term evolution (3GPP LTE) that is a mobile communicationstandardization group, but based on determinations by those skilled inthe art, the main idea of the disclosure may be applied to othercommunication systems having similar backgrounds or channel typesthrough some modifications without significantly departing from thescope of the disclosure.

In a 5G system, in order to support network automation, a network datacollection and analysis function (NWDAF), which is a network functionthat provides a function of analyzing and providing data collected froma 5G network, may be defined. The NWDAF can collect/storage/analyzeinformation from the 5G network to provide the result to an unspecifiednetwork function (NF), and the analysis result can be used independentlyin each NF.

In the following description, the disclosure will be described usingterms and names defined in the 3GPP standards (5G, NR, LTE, or othersimilar system standards) for the convenience of description. However,the disclosure is not limited by these terms and names, and may beapplied in the same way to systems that conform other standards.

Further, in the following description, terms for identifying accessnodes, terms referring to network entities, terms referring to messages,terms referring to interfaces between network entities, terms referringto various identification information, and the like are illustrativelyused for the sake of convenience. Therefore, the disclosure is notlimited by the terms as used below, and other terms referring tosubjects having equivalent technical meanings may be used.

Unlike the LTE system, the 5G communication system resources varioussubcarrier spacings, such as 30 kHz, 60 kHz, and 120 kHz, including 15kHz, the physical control channel uses polar coding, and the physicaldata channel uses low density parity check (LDPC). In addition, as awaveform for uplink transmission, not only DFT-S-OFDM but also CP-OFDMare used. In LTE, while hybrid ARQ (HARQ) retransmission in units oftransport block (TB) is resourced, in 5G, it is possible to additionallyresource HARQ retransmission based on a code block group (CBG) in whichseveral code blocks (CBs) are grouped.

As described above, various services can be provided to users in the 5Gcommunication system, and in order to provide such various services tousers, a method and an apparatus using the same are required to provideeach service according to characteristics within the same time period.Various services provided in 5G communication systems are being studied,and one of them is a service that satisfies the requirements for lowlatency and high reliability.

In the case of vehicle communication, the NR vehicle-to-everything (V2X)system supports unicast communication, groupcast (or multicast)communication, and broadcast communication between terminals. Inaddition, unlike LTE V2X system, which aims to transmit and receivebasic safety information necessary for vehicle driving on the road, theNR V2X system aims to provide more advanced services, such as groupdriving (platooning), advanced driving, extended sensor, and remotedriving. In addition, the NR V2X system supports a method in which theterminal directly detects and allocates sidelink transmission resourcesbased on both periodic and aperiodic traffic. However, especially in thecase of a pedestrian mobile terminal, a method and procedure forselecting a transmission resource by minimizing power consumption of theterminal may be required. Therefore, the operations of a terminal and abase station for solving this problem should be defined. However, thereis no discussion about this. Accordingly, the disclosure proposes asensing and resource assignment method that optimizes power consumptionof a terminal in a sidelink. In addition, the disclosure also proposes aDMRS transmission/reception method for such sidelink data.

Embodiments have been proposed to support the above-described scenario,and in particular, a purpose of the disclosure is to provide a methodand an apparatus for minimizing power consumption of a terminal duringsensing and resource selection processes by a terminal in a sidelink.

FIG. 1A is a view illustrating a system according to an embodiment ofthe disclosure, FIG. 1B is a view illustrating a system according to anembodiment of the disclosure, FIG. 1C is a view illustrating a systemaccording to an embodiment of the disclosure, and FIG. 1D is a viewillustrating a system according to an embodiment of the disclosure.

Referring to FIGS. 1A to 1D, FIG. 1A illustrates a case (in-coverage(IC)) in which all V2X terminals UE1 and UE2 are located within thecoverage area of a base station. All V2X terminals may receive data andcontrol information from the base station through a downlink (DL) ortransmit data and control information to the base station through anuplink (UL). In this case, the data and control information may be dataand control information for V2X communication. The data and controlinformation may be data and control information for general cellularcommunication. In addition, the V2X terminals may transmit/receive dataand control information for V2X communication through a sidelink (SL).

Referring to FIGS. 1A to 1D, FIG. 1B illustrates a case in which UE-1 islocated within the coverage area of a base station and UE-2 is locatedoutside the coverage area of the base station among the V2X terminals.For example, FIG. 1B illustrates partial coverage (PC) in which some V2Xterminals (UE-2) are located outside the coverage area of the basestation. The V2X terminal UE-1 located within the coverage area of thebase station may receive data and control information from the basestation through downlink or transmit data and control information to thebase station through uplink. The V2X terminal UE-2 located outside thecoverage area of the base station cannot receive data and controlinformation from the base station through downlink, and cannot transmitdata and control information to the base station through uplink.Accordingly, the V2X terminal UE-2 can transmit/receive data and controlinformation for V2X communication through the sidelink with the V2Xterminal UE-1.

Referring to FIGS. 1A to 1D, FIG. 1C illustrates a case in which all V2Xterminals are located out of coverage area (OOC) of a base station.Therefore, the V2X terminals UE-1 and UE-2 cannot receive data andcontrol information from the base station through downlink, and cannottransmit data and control information to the base station throughuplink. V2X terminals UE-1 and UE-2 can transmit/receive data andcontrol information for V2X communication through the sidelink.

Referring to FIGS. 1A to 1D, FIG. 1D illustrates a scenario forperforming V2X communication between V2X terminals UE-1 and UE-2 locatedin different cells. Specifically, FIG. 1D illustrates a case in whichthe V2X terminals UE-1 and UE-2 are connected to different base stations(RRC connection state) or camping (RRC connection release state, thatis, RRC idle state). In this case, the V2X terminal UE-1 may be a V2Xtransmitting terminal and the V2X terminal UE-2 may be a V2X receivingterminal. Alternatively, the V2X terminal UE-1 may be a V2X receivingterminal, and the V2X terminal UE-2 may be a V2X transmitting terminal.The V2X terminal UE-1 may receive a system information block (SIB) fromthe base station to which it has accessed (or on which it is camping),and the V2X terminal UE-2 may receive an SIB from another base stationto which it is connected (or on which it is camping). In this case, asthe SIB, an existing SIB may be used, or a separately defined SIB forV2X may be used. In addition, information of the SIB received by the V2Xterminal UE-1 and information of the SIB received by the V2X terminalUE-2 may be different from each other. Therefore, in order to performV2X communication between terminals UE-1 and UE-2 located in differentcells, a method of interpreting SIB information transmitted fromdifferent cells may be additionally required by unifying the informationor by signaling the information.

In FIGS. 1A to 1D, for convenience of description, a V2X systemconsisting of V2X terminals UE-1 and UE-2 is illustrated, but thedisclosure is not limited thereto, and communication between more V2Xterminals may be achieved. In addition, the interface (uplink anddownlink) between the base station and the V2X terminals may be referredto as Uu interfaces, and the sidelink between the V2X terminals may bereferred to as the PC5 interface. Therefore, in the disclosure, theterms can be mixed and used. Meanwhile, in the disclosure, the terminalmay include a vehicle that supports vehicle-to-vehicular communication(vehicular-to-vehicular (V2V)), a vehicle that supportsvehicle-to-pedestrian communication (vehicular-to-pedestrian (V2P)) or apedestrian's handset (e.g., a smartphone), a vehicle that supportscommunication between networks (vehicular-to-network, V2N), or a vehiclethat supports communication between a vehicle and a transportationinfrastructure (vehicular-to-infrastructure (V2I)). In addition, in thedisclosure, the terminal may include a road side unit (RSU) equippedwith a terminal function, an RSU equipped with a base station function,or an RSU equipped with a part of the base station function and a partof the terminal function.

Further, according to an embodiment of the disclosure, the base stationmay be a base station supporting both V2X communication and generalcellular communication, or may be a base station supporting only V2Xcommunication. In this case, the base station may be a 5G base station(gNB), a 4G base station (eNB), or an RSU. Therefore, in thisdisclosure, the base station may be referred to as an RSU.

FIG. 2A is a diagram illustrating a V2X communication method performedthrough a sidelink according to an embodiment of the disclosure, andFIG. 2B is a diagram illustrating a V2X communication method performedthrough a sidelink according to an embodiment of the disclosure.

Referring to FIG. 2A, UE-1 201 (e.g., TX terminal) and UE-2 202 (e.g.,RX terminal) can perform one-to-one communication, and it can be calledunicast communication.

Referring to FIG. 2B, the TX terminal and the RX terminal may performone-to-many communication, which may be referred to as groupcast ormulticast. In FIG. 2B, UE-1 211, UE-2 212, and UE-3 213 may form a group(Group A) to perform groupcast communication, and, UE-4 214, UE-5 215,UE-6 216, and UE-7 217 may form another group (Group B) to performgroupcast communication. Each terminal performs groupcast communicationonly within a group to which it belongs, and communication betweendifferent groups may be performed through unicast, groupcast, orbroadcast communication. FIG. 2B illustrates that two groups (Group Aand Group B) are formed, but are not limited thereto.

Meanwhile, although not illustrated in FIGS. 2A and 2B, the V2Xterminals may perform broadcast communication. Broadcast communicationrefers to a case where all V2X terminals receive data and controlinformation transmitted by a V2X transmitting terminal through asidelink. As an example, if it is assumed that UE-1 211 is atransmitting terminal for broadcast in FIG. 2B, all terminals UE-2 212,UE-3 213, UE-4 214, UE-5 215, UE-6 216, and UE-7 217 may receive dataand control information transmitted by UE-1 211.

In NR V2X, unlike in LTE V2X, support in a form in which a vehicleterminal transmits data to only one specific node through unicast and aform in which data is transmitted to a plurality of specific nodesthrough groupcast may be considered. For example, in a service scenario,such as Platooning, which is a technology that connects two or morevehicles through a single network and moves in a cluster form, suchunicast and group cast technologies may be usefully used. Specifically,unicast communication may be required for the purpose of a group leadernode connected by platooning to control one specific node, and groupcast communication may be required for the purpose of simultaneouslycontrolling a group consisting of a specific number of nodes.

FIG. 3 is a diagram illustrating a resource pool defined as a set ofresources on a time and frequency used for transmission and reception ofa sidelink according to an embodiment of the disclosure.

In the resource pool, the resource granularity of the time axis may be aslot. In addition, the resource assignment unit on the frequency axismay be a subchannel including one or more physical resource blocks(PRBs).

When the resource pool is assigned on time and frequency (310), acolored area indicates a region set as a resource pool on time andfrequency. In the disclosure, an example of a case in which the resourcepool is non-contiguously assigned over time is described, but theresource pool may be continuously assigned over time. In addition,although the disclosure describes an example in which a resource pool iscontinuously assigned on a frequency, a method in which the resourcepool is non-contiguously assigned on a frequency is not excluded.

Referring to FIG. 3, a case 320 in which a resource pool is assignednon-contiguously over time is illustrated. Referring to FIG. 3, a casein which a granularity of resource assignment over time is made of aslot is illustrated. Specifically, one slot including a plurality ofOFDM symbols may be a basic unit of resource assignment on the timeaxis. In this case, all OFDM symbols constituting the slot may be usedfor sidelink transmission, or some of the OFDM symbols constituting theslot may be used for sidelink transmission. For example, some of theslots may be used as downlink/uplink used as a Uu interface between basestation terminals. Referring to FIG. 3, a colored slot represents a slotincluded in a resource pool in time, and a slot assigned to the resourcepool may be (pre-)configurated with resource pool information in time.For example, resource pool information in time may be indicated as abitmap through the SIB.

Referring to FIG. 3, a physical slot 320 belonging to a non-contiguousresource pool in time may be mapped to a logical slot 321. In general, aset of slots belonging to a physical sidelink shared channel (PSSCH)resource pool may be represented by (t0, t1, . . . , ti, . . . , tTmax).

Referring to FIG. 3, a case 330 in which a resource pool is continuouslyassigned on a frequency is illustrated.

Resource assignment in the frequency axis may be performed in units ofsub-channels 331. The subchannel 331 may be defined as a resourceassignment unit on a frequency including one or more RBs. For example,the subchannel 331 may be defined as an integer multiple of RB.Referring to FIG. 3, a subchannel 3-31 may be including five consecutivePRBs, and a size of a subchannel (sizeSubchannel) may be a size of fiveconsecutive PRBs. However, the contents illustrated in the drawings areonly an example of the disclosure, and the size of the subchannel may beconfigured differently, and one subchannel is generally configured as acontinuous PRB, but it is not necessarily configured as a continuousPRB. The subchannel 331 may be a basic unit of resource assignment forPSSCH.

The startRB-Subchannel 332 may indicate the start position of thesubchannel 331 on a frequency in the resource pool. When resourceassignment is performed in units of subchannels 331 on the frequencyaxis, resources on a frequency may be assigned through configurationinformation about the RB index (startRB-Subchannel, 332) at which thesubchannel 331 starts, information on how many RBs the subchannel 331consists of (sizeSubchannel), the total number of subchannels 331(numSubchannel), or the like. In this case, information about thestartRB-Subchannel, sizeSubchannel, and numSubchannel may be(pre-)configurated as resource pool information on frequency. Forexample, the frequency resource pool information may be configured andindicated through the SIB.

FIG. 4 is a diagram illustrating a method for a base station to assigntransmission resources in a sidelink according to an embodiment of thedisclosure.

A method for the base station to assign transmission resources in thesidelink will be referred to as Mode 1 below. Mode 1 may be a scheduledresource assignment. Mode 1 may represent a method in which the basestation allocates resources used for sidelink transmission toRRC-connected terminals in a dedicated scheduling scheme. The mode 1method may be effective for interference management and resource poolmanagement because the base station can manage the resources of thesidelink.

Referring to FIG. 4, a transmitting terminal 401 and a receivingterminal 402 camping on (405) may receive a sidelink system informationblock (SL-SIB) from the base station 403 (410). Here, the receivingterminal 402 represents a terminal that receives data transmitted by thetransmitting terminal 401. The SL-SIB information may include sidelinkresource pool information for sidelink transmission/reception, parametersetting information for sensing operation, information for settingsidelink synchronization, or carrier information for sidelinktransmission/reception operating at different frequencies.

When data traffic for V2X is generated in the transmitting terminal 401,the transmitting terminal 401 may be RRC connected to the base station403 (420). Here, the RRC connection between the terminal and the basestation may be referred to as Uu-RRC. The Uu-RRC connection process 420may be performed before the transmission terminal 401 generates datatraffic. In addition, in Mode 1, while the Uu-RRC connection process 420between the base station 403 and the receiving terminal 402 isperformed, the transmitting terminal may perform transmission to thereceiving terminal through a sidelink. In contrast, in Mode 1, thetransmitting terminal may perform transmission to the receiving terminalthrough the sidelink even when the Uu-RRC connection process 420 betweenthe base station 403 and the receiving terminal 402 is not performed.

The transmitting terminal 401 may request a transmission resourcecapable of V2X communication with the receiving terminal 402 from thebase station (430). In this case, the transmitting terminal 401 mayrequest a sidelink transmission resource from the base station 403 usingan uplink physical uplink control channel (PUCCH), an RRC message, or aMAC CE. Meanwhile, the MAC CE may be a buffer status report (BSR) MAC CEof a new format (including at least an indicator indicating that thebuffer status report for V2X communication and information on the sizeof data buffered for D2D communication). In addition, the transmittingterminal 401 may request a sidelink resource through a schedulingrequest (SR) bit transmitted through an uplink physical control channel.

Thereafter, the base station 403 may assign a V2X transmission resourceto the transmission terminal 401. In this case, the base station mayassign transmission resources in a dynamic grant scheme or a configuredgrant scheme.

First, in the case of the dynamic grant scheme, the base station mayassign resources for TB transmission through downlink controlinformation (DCI). The sidelink scheduling information included in theDCI may include parameters related to the initial transmission andretransmission transmission time and frequency assignment locationinformation fields. The DCI for the dynamic grant method may be cyclicredundancy check (CRC) scrambled with SL-V-radio network temporaryidentifier (RNTI) to indicate that it is a dynamic grant scheme.

Thereafter, in the case of the configured grant scheme, the base stationmay periodically assign resources for TB transmission by configuring asemi-persistent scheduling (SPS) interval through Uu-RRC. In this case,the base station may assign resources for one TB through DCI. Sidelinkscheduling information for one TB included in the DCI may includeparameters related to initial transmission and retransmission resourcetransmission times and frequency assignment location information. Whenresources are assigned in the configured grant scheme, the transmissiontime (occasion) and frequency assignment position of the initialtransmission and retransmission for one TB may be determined by the DCI,and the resource for the next TB may be repeated at SPS intervalintervals. DCI for the configured grant scheme may be CRC scrambled withSL-SPS-V-RNTI to indicate that the configured grant scheme. In addition,the configured grant (CG) scheme can be divided into type1 CG and type2CG. In the case of Type2 CG, it is possible to activate/deactivationresources set as configured grant through DCI.

Therefore, in the case of Mode 1, the base station 403 may instruct thetransmitting terminal 401 to schedule for sidelink communication withthe receiving terminal 402 through DCI transmission through the PDCCH(440).

In the case of broadcast transmission, the transmitting terminal 401 maybroadcast the SCI (1st stage) to the receiving terminal 402 through thePSCCH by broadcast without the RRC configuration 415 for the sidelink(460). In addition, the transmitting terminal 401 may broadcast data tothe receiving terminal 402 through the PSSCH (480). In the case ofbroadcast transmission, SCI transmission (2nd stage SCI 470) throughPSSCH might not be performed.

In contrast, in the case of unicast or groupcast transmission, thetransmitting terminal 401 may perform a one-to-one RRC connection withanother terminal Here, the RRC connection between terminals may bereferred to as PC5-RRC 415, distinguishing it from Uu-RRC. Even in thecase of groupcast, the PC5-RRC 415 may be individually connected betweenthe terminal and the terminal in the group. Referring to FIG. 4,although the connection of the PC5-RRC 415 is shown as an operationafter transmission 410 of SL-SIB, it may be performed at any time beforetransmission 410 of SL-SIB or transmission of SCI. If the RRC connectionbetween the terminals is required, the PC5-RRC connection of thesidelink may be performed, and the transmitting terminal 401 maytransmit the SCI (1st stage) to the receiving terminal 402 through thePSCCH in unicast or groupcast (460). In this case, the groupcasttransmission of SCI may be interpreted as a group SCI. In addition, thetransmitting terminal 401 may transmit the SCI (2nd stage) to thereceiving terminal 402 through the PSSCH in unicast or groupcast (470).In this case, information related to resource assignment may be includedin the 1st stage SCI, and control information other than that may beincluded in the 2nd stage SCI. In addition, the transmitting terminal401 may transmit data to the receiving terminal 402 through the PSSCH inunicast or groupcast (480).

FIG. 5 is a diagram illustrating a method of directly assigning atransmission resource of a sidelink through sensing by a terminal in asidelink according to an embodiment of the disclosure. Hereinafter, amethod in which the UE directly allocates sidelink transmissionresources through sensing in the sidelink is referred to as Mode 2. Inthe case of Mode 2, it may also be referred to as UE autonomous resourceselection.

Referring to FIG. 5, in Mode 2, a base station 503 may provide a pool ofsidelink transmission/reception resources for V2X as system information,and a transmission terminal 501 may select a transmission resourceaccording to a predetermined rule. Unlike Mode 1, in which the basestation is directly involved in resource assignment, in FIG. 5, there isa difference in that the transmitting terminal 501 autonomously selectsa resource and transmits data, based on a resource pool previouslyreceived through system information.

Referring to FIG. 5, the transmitting terminal 501 and a receivingterminal 502 camping on (505) may receive SL-SIBs from the base station503 (510). Here, a receiving terminal 502 represents a terminal thatreceives data transmitted by the transmitting terminal 501. The SL-SIBinformation may include sidelink resource pool information for sidelinktransmission/reception, parameter configuration information for sensingoperation, information for configuring sidelink synchronization, orcarrier information for sidelink transmission/reception operating atdifferent frequencies.

The difference between FIG. 4 and FIG. 5 is that, in the case of FIG. 4,the base station 503 and the terminal 501 operate in an RRC connectedstate, while in FIG. 5, the terminal can operate in an idle mode 520 (astate in which RRC is not connected). In addition, even in the RRCconnection state 520, the base station 503 does not directly participatein resource assignment and allows the transmitting terminal 501 toautonomously select a transmission resource. Here, the RRC connectionbetween the terminal 501 and the base station 503 may be referred to asa Uu-RRC (520). When data traffic for V2X is generated in thetransmitting terminal 501, the transmitting terminal 501 may beconfigured with a resource pool through system information received fromthe base station 503, and the transmitting terminal 501 may directlyselect a resource in the time/frequency domain through sensing withinthe configured resource pool (530).

In the case of broadcast transmission, the transmitting terminal 501 maybroadcast the SCI (1st stage) to the receiving terminal 502 through thePSCCH by broadcast without the RRC configuring (520) for the sidelink(550). In addition, the transmitting terminal 501 may broadcast data tothe receiving terminal 502 through the PSSCH (570). In the case ofbroadcast transmission, SCI transmission (2nd stage SCI 560) throughPSSCH might not be performed.

In contrast, in the case of unicast and groupcast transmission, thetransmitting terminal 501 may perform a one-to-one RRC connection withother terminals. Here, separate from Uu-RRC, the RRC connection betweenterminals may be PC5-RRC. Even in the case of groupcast, PC5-RRC may beindividually connected between terminals in the group. In FIG. 5, theconnection of the PC5-RRC 515 is illustrated as an operation aftertransmission 510 of SL-SIB, but may be performed at any time beforetransmission 510 of SL-SIB or transmission 550 of SCI. If the RRCconnection between the terminals is required, the sidelink PC5-RRCconnection may be performed (515), and the transmitting terminal 501 maytransmit the SCI (1st stage) to the receiving terminal 502 through thePSCCH in unicast or groupcast (550). In this case, the groupcasttransmission of SCI may be interpreted as a group SCI. In addition, thetransmitting terminal 501 may transmit the SCI (2nd stage) to thereceiving terminal 502 through the PSSCH in unicast or groupcast (560).In this case, information related to resource assignment may be includedin the 1st stage SCI, and control information other than that may beincluded in the 2nd stage SCI. In addition, the transmitting terminal501 may transmit data to the receiving terminal 502 through the PSSCH inunicast or groupcast (570).

FIG. 6 is a diagram illustrating a mapping structure of physicalchannels mapped to one slot in a sidelink according to an embodiment ofthe disclosure.

Referring to FIG. 6, illustrates mapping for PSCCH/PSSCH/PSFCH physicalchannels. PSCCH/PSSCH/PSFCH may be assigned to one or more subchannelson a frequency domain. For details on subchannel assignment, thedescription of FIG. 3 will be referred. Thereafter, referring to FIG. 6to describe the temporal mapping of PSCCH/PSSCH/PSFCH, one or moresymbols before the transmitting terminal transmits the PSCCH/PSSCH/PSFCHin the corresponding slot 601 may be used as the region 602 for the AGC.When the corresponding symbol(s) is used for AGC, a method of repetitionand transmission of signals of other channels in the correspondingsymbol region 602 may be considered. In this case, a part of a PSCCHsymbol or a PSSCH symbol may be considered for the repeated signal ofanother channel. Alternatively, a preamble may be transmitted to the AGCregion 602. When a preamble signal is transmitted, there is an advantagein that the AGC execution time can be shorter than a method ofrepeatedly transmitting signals of other channels. When a preamblesignal is transmitted for AGC, a specific sequence may be used as thepreamble signal 602, and in this case, a sequence, such as PSSCH DMRS,PSCCH DMRS, and CSI-RS may be used as the preamble. The sequence used asa preamble in the disclosure is not limited to the above-describedexample.

Additionally, according to FIG. 6, a PSCCH 603 including controlinformation may be transmitted in initial symbols of a slot, and datascheduled by the control information of the PSCCH 603 may be transmittedto the PSSCH 604. A part (1st stage SCI) of sidelink control information(SCI), which is control information, may be mapped to the PSCCH 603 andtransmitted. In the PSSCH 604, not only data information, but alsoanother part (2nd stage SCI) of SCI, which is control information, maybe mapped and transmitted. In addition, FIG. 6 illustrates that aphysical sidelink feedback channel (PSFCH 605), which is a physicalchannel for transmitting feedback information, is located at the end ofa slot. A predetermined vacant time (Gap) may be secured between thePSSCH 604 and the PSFCH 605 so that the UEs that havetransmitted/received the PSSCH 604 can prepare to transmit or receivethe PSFCH 605. In addition, after transmission and reception of thePSFCH 605, an empty section (Gap) can be secured for a predeterminedtime.

FIG. 7 is a diagram illustrating a method of selecting a resource andreselecting a resource by a terminal in Mode 2 according to anembodiment of the disclosure.

Referring to FIG. 7, it illustrates a case in which triggering forresource selection is performed at time n, and triggering forre-evaluation is performed at n′ (n′>n) by continuously sensing evenafter triggering time n. Referring to FIG. 7, when triggering forresource selection is performed at time n, the sensing window may bedefined as [n−T0, n−Tproc,0). Here, T0 is the starting point of thesensing window and may be (pre-)configurated as resource poolinformation. In addition, Tproc,0 may be defined as a time required toprocess the sensing result, and the required Tproc,0 may vary accordingto the configured T0 value. Specifically, when a long T0 value isconfigured, a long Tproc,0 may be required. Conversely, when a short T0value is configured, a short Tproc,0 may be required. Accordingly, theTproc,0 value may be fixed to one value, but another value adjusted bythe configured T0 value may be (pre-) configurated as resource poolinformation. Thereafter, when triggering for resource selection isperformed at time n, the resource selection window may be determined as[n+T1, n+T2]. Here, T1 may be selected as a terminal implementation forT1≤Tproc,1. Tproc,1 is the maximum reference value in which theprocessing time required to select a resource is considered, and sincethis processing time may vary according to the terminal implementation,T1 may be selected as a value less than Tproc,1 by the terminalimplementation. In addition, assuming that T2 is configured to selectNmax resources for one TB, the resources of Nmax may include initialtransmission and retransmission resources. In this case, the UE selectsT2 within a range that satisfies the T2≤Packet delay budget (PDP).Thereafter, when triggering for re-evaluation occurs at n′ (n′>n) bycontinuously performing sensing even after triggering, referring to FIG.7, this means that when at least an already selected resource is in slotm (701), triggering for reselection should be performed before m-T3.Here, T3 may be a processing time required for re-selection. As a firstmethod, a method of using the resource selection processing time T1already selected according to the UE implementation as T3 as it is canbe considered (T3=T1). However, in the re-evaluation process, additionalprocessing time for resource selection may be required. Specifically,time required for dropping the previously selected resource may berequired, as well as the time required to process it in a case where theprevious resource and the new resource overlap. Therefore, a method ofconfiguring T3=Tproc,1 can be considered. This is because Tproc,1 is themaximum reference value in which the processing time required to selecta resource is considered, so if triggering for reselection is performedbefore the corresponding value, it may be possible to change theselected resource to another resource. As illustrated in FIG. 7, whentriggering for re-evaluation occurs at n′ (n′>n), the sensing window forthis may be [n′−T0, n′−Tproc,0], and the resource selection window forthis may be determined as [n′+T1, n′+T2]. In this case, the value of T0and Tproc,0 may be the same values as the values used when triggeringfor resource selection is performed at time n. However, for T1 and T2,depending on the implementation, the terminal may select the same valueas at point n when triggering for resource selection is performed, butother values may be selected.

FIG. 8 is a diagram illustrating a process in which one transport blockis divided into several code blocks and a CRC is added according to anembodiment of the disclosure.

Referring to FIG. 8, a CRC 8-03 may be added to the last or first partof one transport block 8-01 to be transmitted in uplink or downlink. TheCRC may have 16 bits or 24 bits, a predetermined number of bits, or avariable number of bits according to a channel condition, and may beused to determine whether channel coding is successful. The blocks 8-01and 8-03 to which the CRC is added to the TB can be divided into severalcode blocks (CBs), 8-07, 8-09, 8-11, and 8-13) (8-05). The maximum sizeof the code blocks may be predetermined and thus can be divided. In thiscase, the last code block 8-13 may be smaller in size than other codeblocks, or may be adjusted to have the same length as other code blocksby inserting 0, a random value, or 1. CRCs 8-17, 8-19, 8-21, and 8-23may be added to the divided code blocks (8-15). The CRC may have 16bits, 24 bits, or a predetermined number of bits, and may be used todetermine whether channel coding is successful.

To generate the CRC 8-03, the TB 8-01 and a cyclic generator polynomialmay be used, and the cyclic generation polynomial may be defined invarious ways. For example, assuming a cyclic generation polynomialg_(CRC24A)(D)=[D²⁴+D²³+D¹⁸+D¹⁷+D¹⁴+D¹¹+D¹⁰+D⁷+D⁶+D⁵+D⁴+D³+D+1] for24-bit CRC, and assuming L=24, for TB data a₀, a₁, a₂, a₃, . . . ,a_(A−1), CRC p₀, p₁, p₂, p₃, . . . , p_(L−1) dividesa₀D^(A+23)+a₁D^(A+22)+ . . . +a_(A−1)D²⁴+p₀D²³+p₁D²²+ . . . +p₂₂D¹+p₂₃by g_(CRC24A)(D) to determine p₀, p₁, p₂, p₃, . . . , p_(L−1) as a valuewhose remainder becomes 0. An example in which the CRC length L is 24has been described above, but the length may be determined in variouslengths, such as 12, 16, 24, 32, 40, 48, 64, or the like.

After adding the CRC to the TB through the above process, thetransmitter divides it into N CBs 8-07, 8-09, 8-11, 8-13 (8-05). CRCs8-17, 8-19, 8-21, 8-23 are added to each of the divided CBs 8-07, 8-09,8-11, and 8-13 (8-15). As for the CRC added to the CB, a CRC of a lengthdifferent from when generating the CRC added to the TB or a differentcyclic generation polynomial may be used. However, the CRC 803 added tothe TB and the CRCs 8-17, 8-19, 8-21, and 8-23 added to the code blockmay be omitted depending on the type of channel code to be applied tothe code block. For example, when a low-density parity-check (LDPC) coderather than a turbo code is applied to a code block, the CRCs 8-17,8-19, 8-21, and 8-23 to be inserted for each code block may be omitted.However, even when LDPC is applied, the CRCs 8-17, 8-19, 8-21, and 8-23may be added to the code block as it is. In addition, even when a polarcode is used, a CRC may be added or omitted.

As described above in FIG. 8, as for the TB to be transmitted, themaximum length of one code block may be determined according to the typeof channel coding applied, and the TB and the CRC added to the TB may bedivided into code blocks depending on the maximum length of the codeblock.

In the LTE system of the related art, a CRC for CB is added to thedivided CB, the data bits and CRC of the CB are encoded with a channelcode, coded bits are determined, and the number of rate-matched bits maybe determined for each of the coded bits as promised in advance.

The following embodiment is to propose a method for minimizing powerconsumption of the terminal in the process (Mode 2) of the terminalperforming sensing and resource selection in the above-describedsidelink. The embodiment relates to the operation of the terminal andthe base station according to the proposed method.

First Embodiment

The first embodiment provides a method and an apparatus for assigning afrequency-time resource to a receiving terminal in a process in which aterminal performs sensing and resource selection and transmits data in asidelink.

The information for assigning up to Nmax frequency-time resources may betransmitted by the transmitting terminal to the receiving terminal insidelink control information. The Nmax may be a configured value, andfor example, may be set to 2 or 3. For example, when Nmax is configuredas 3, up to 3 pieces of resource assignment information may be deliveredin SCI. Of course, when Nmax is configured as 3, only one piece ofresource assignment information may be delivered, or only two pieces ofresource assignment information may be delivered, or three pieces ofresource assignment information may be delivered. The range offrequency-time resources that can be assigned in the above may be givenby W. For example, the time range of the assigned resources that can beindicated by the SCI may be W. The W may be given as the number ofslots. For example, W may be given as 32, which is capable of deliveringNmax resource assignment information within 32 slots in SCI.

FIGS. 9A, 9B and 9C are diagrams illustrating one, two, or threefrequency-time resources are assigned and indicated according to anembodiment of the disclosure. Assigning a frequency-time resource may beapplied by combining one or more of the following methods. In thefollowing, it may be a method of separately indicating frequencyresources and time resources. In the following, it is described as anexample of a case where W=32, that is, a time resource selection rangeof 32 slots, and when W is changed and applied, the size of the resourceassignment bitfield required in SCI may be changed and applied.

-   -   Time resource assignment method 1: This method provides an        example when Nmax=2 is configured. A 5-bit bitfield is used for        time resource assignment, and when the value indicated by the        5-bit is T, the first resource is a resource assigned in the        slot (e.g., slot n) in which SCI is transmitted, and the second        resource is a resource assigned in n+T. In this method, T may be        a value obtained by converting the 5-bit indication value into a        decimal number. If the value indicated by the 5 bits is 0, that        is, T=0, the second resource may be regarded as not allocated.        If T=0, the second frequency resource information indicated in        the same SCI may be ignored. Alternatively, if T=0, the second        frequency resource information indicated in the same SCI may be        a value used for another purpose.    -   Time resource assignment method 2: This method provides an        example when Nmax=3 is configured. Two 5-bit bitfields are used        for time resource assignment, and when the values indicated by        each of the five bits of each bitfield are T1 and T2, the first        resource is assigned in the slot (slot n) in which SCI is        transmitted. The second resource is a resource assigned from        n+T1, and the third resource is a resource assigned from n+T2.        In the above, the order of the second and third resources may be        changed according to the values of T1 and T2. In this method, T1        and T2 may be values obtained by converting values indicated in        the 5-bit bitfields into decimal numbers. If a value indicated        by 5 bits among the above bitfields is 0, that is, T1=0 or T2=0,        the second resource or the third resource may be regarded as not        allocated. In addition, if T1=0 and T2=0, the second resource        and the third resource may be regarded as unallocated, and in        this case, the TB may be transmitted only in a slot in which SCI        is transmitted. If T1=0 or T2=0, second or third frequency        resource information indicated in the same SCI may be ignored.        In this method, if only two resources are to be allocated,        forcing T2=0 and T1 to indicate the second resource can be        applied. In this case, the time position of the first resource        will be T0=0. On the contrary, in this method, if only two        resources are to be allocated, forcing T1=0 and T2 to indicate        the second resource may be applied. In this case, the time        position of the first resource will be T0=0.    -   Time resource assignment method 3: This method provides an        example when Nmax=3 is configured. One bitfield is used for time        resource assignment, and T1 and T2 can be interpreted by the        bitfield value. When the bitfield value is r, r may be        determined by Equation 1 below.

$\begin{matrix}{r = {{\sum\limits_{i = 0}^{N - 2}\begin{pmatrix}{W - 1} \\i\end{pmatrix}} + {\sum\limits_{i = 0}^{N - 2}{\langle\begin{matrix}{W - 1 - T_{i + 1}} \\{N - 1 - i}\end{matrix}\rangle}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

In the above equation, N is the number of resources assigned by SCI, andmay be N=0 or N=1 or N=2. In the above, W is a time range in which aresource can be selected as described above. In the above equation, T1refers to a time slot of the i-th resource, and in the disclosure, T0refers to T0=0 as the first resource, and T1 and T2 indicate time slotinformation of the second and third resources, respectively, and may bea slot offset from the first resource.

In the Equation,

${\langle\begin{matrix}x \\y\end{matrix}\rangle}\quad$

is an extended binomial operation defined by

${\langle\begin{matrix}x \\y\end{matrix}\rangle} = \left\{ \begin{matrix}\begin{pmatrix}x \\y\end{pmatrix} & {x \geq y} \\o & {{x < y},\mspace{14mu} {{and}\begin{pmatrix}x \\y\end{pmatrix}}}\end{matrix} \right.$

may represent the number of cases in which y is subtracted from x, andmay be a binary coefficient. According to Equation 1, the value of r isdetermined within the range of Equation 2 below.

$\begin{matrix}\left\{ {0,1,\ldots \mspace{14mu},{{\sum\limits_{i = 0}^{N_{\max} - 1}\begin{pmatrix}{W - 1} \\i\end{pmatrix}} - 1}} \right\} & {{Equation}\mspace{14mu} 2}\end{matrix}$

Accordingly, compared to the time resource assignment method 2, thenumber of bits for indicating T1 and T2 can be saved, and the size of abitfield applied in this method may be determined as

$\left\lceil {\log_{2}\left( {\sum_{i = 0}^{N_{\max} - 1}\begin{pmatrix}W \\i\end{pmatrix}} \right)} \right\rceil \mspace{14mu} {{bits}.}$

In the above, ┌x┐ may be a value rounded up from x, or may indicate aminimum integer greater than or equal to x.

Referring to FIG. 9A, as an example, consider the case where W=32 andNmax=3. In this case,

$\left\lceil {\log_{2}\left( {\sum_{i = 0}^{2}\begin{pmatrix}31 \\i\end{pmatrix}} \right)} \right\rceil = 9$

bits are needed to apply this method. When only one frequency-timeresource is allocated, that is, when N=1, Equation 1 may be applied tothe following Equation 3.

r=0  Equation 3

For example, T0=0, and T1 and T2 are not set to be negligible.

Referring to FIG. 9B, when only two frequency-time resources areallocated, that is, when N=2, Equation 3 can be applied to the followingEquation 4.

$\begin{matrix}{r = {1 + {\langle\begin{matrix}{31 - T_{1}} \\1\end{matrix}\rangle}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

That is, assuming T0=0, r is determined as shown in Table 1 belowaccording to the value of T1, and the value of T2 is not determined soas to be negligible.

TABLE 1 T1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 2324 25 r 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 1110 9 8 7 T1 26 27 28 29 30 31 r 6 5 4 3 2 1

Referring to FIG. 9C, when three frequency-time resources are allocated,that is, when N=3, Equation 1 can be applied to the following Equation5.

$\begin{matrix}\begin{matrix}{r = {{{\sum\limits_{i = 0}^{1}\begin{pmatrix}31 \\i\end{pmatrix}} + {\sum\limits_{i = 0}^{i}\; {\langle\begin{matrix}{31 - T_{i + 1}} \\{2 - i}\end{matrix}\rangle}}} = {32 + {\langle\begin{matrix}{31 - T_{1}} \\2\end{matrix}\rangle} + {\langle\begin{matrix}{31 - T_{2}} \\1\end{matrix}\rangle}}}} & \mspace{14mu}\end{matrix} & {{Equation}\mspace{14mu} 5}\end{matrix}$

That is, assuming T0=0, r is determined as shown in Table 2 belowaccording to the values of T1 and T2.

TABLE 2 T1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T2 2 496 XX X X X X X X X X X X X X X X X X X 3 495 466 X X X X X X X X X X X X XX X X X X 4 494 465 437 X X X X X X X X X X X X X X X X X 5 493 464 436409 X X X X X X X X X X X X X X X X 6 492 463 435 408 382 X X X X X X XX X X X X X X X 7 491 462 434 407 381 356 X X X X X X X X X X X X X X 8490 461 433 406 380 355 331 X X X X X X X X X X X X X 9 489 460 432 405379 354 330 307 X X X X X X X X X X X X 10 488 459 431 404 378 353 329306 284 X X X X X X X X X X X 11 487 458 430 403 377 352 328 305 283 262X X X X X X X X X X 12 486 457 429 402 376 351 327 304 282 261 241 X X XX X X X X X 13 485 456 428 401 375 350 326 303 281 260 240 221 X X X X XX X X 14 484 455 427 400 374 349 325 302 280 259 239 220 202 X X X X X XX 15 483 454 426 399 373 348 324 301 279 258 238 219 201 184 X X X X X X16 482 453 425 398 372 347 323 300 278 257 237 218 200 183 167 X X X X X17 481 452 424 397 371 346 322 299 277 256 236 217 199 182 166 151 X X XX 18 480 451 423 396 370 345 321 298 276 255 235 216 198 181 165 150 136X X X 19 479 450 422 395 369 344 320 297 275 254 234 215 197 180 164 149135 122 X X 20 478 449 421 394 368 343 319 296 274 253 233 214 196 179163 148 134 121 109 X 21 477 448 420 393 367 342 318 295 273 252 232 213195 178 162 147 133 120 108 97 22 476 447 419 392 366 341 317 294 272251 231 212 194 177 161 146 132 119 107 96 23 475 446 418 391 365 340316 293 271 250 230 211 193 176 160 145 131 118 106 95 24 474 445 417390 364 339 315 292 270 249 229 210 192 175 159 144 130 117 105 94 25473 444 416 389 363 338 314 291 269 248 228 209 191 174 158 143 129 116104 93 26 472 443 415 388 362 337 313 290 268 247 227 208 190 173 157142 128 115 103 92 27 471 442 414 387 361 336 312 289 267 246 226 207189 172 156 141 127 114 102 91 28 470 441 413 386 360 335 311 288 266245 225 206 188 171 155 140 126 113 101 90 29 469 440 412 385 359 334310 287 265 244 224 205 187 170 154 139 125 112 100 89 30 468 439 411384 358 333 309 286 264 243 223 204 186 169 153 138 124 111  99 88 31467 438 410 383 357 332 308 285 263 242 222 203 185 168 152 137 123 110 98 87 T1 21 22 23 24 25 26 27 28 29 30 31 T2 2 X X X X X X X X X X X 3X X X X X X X X X X X 4 X X X X X X X X X X X 5 X X X X X X X X X X X 6X X X X X X X X X X X 7 X X X X X X X X X X X 8 X X X X X X X X X X X 9X X X X X X X X X X X 10 X X X X X X X X X X X 11 X X X X X X X X X X X12 X X X X X X X X X X X 13 X X X X X X X X X X X 14 X X X X X X X X X XX 15 X X X X X X X X X X X 16 X X X X X X X X X X X 17 X X X X X X X X XX X 18 X X X X X X X X X X X 19 X X X X X X X X X X X 20 X X X X X X X XX X X 21 X X X X X X X X X X X 22 86 X X X X X X X X X X 23 85 76 X X XX X X X X X 24 84 75 67 X X X X X X X X 25 83 74 66 59 X X X X X X X 2682 73 65 58 52 X X X X X X 27 81 72 64 57 51 46 X X X X X 28 80 71 63 5650 45 41 X X X X 29 79 70 62 55 49 44 40 37 X X X 30 78 69 61 54 48 4339 36 34 X X 31 77 68 60 53 47 42 38 35 33 32 X

That is, given r, information on T1 and T2 can be found.

-   -   Time resource assignment method 4: This method provides an        example when Nmax=3 is configured. One bitfield is used for time        resource assignment, and T1 and T2 may be interpreted by the        bitfield value. When the bitfield value is r, r may be        determined by the following method. In this case, N may be one        of values 1 to 3, and when N is 1, r may have a specific value.        As an example, r may be determined to be 0. In this case, the        time resource assignment may indicate that only the first        resource indicating T0=0 is allocated. As another embodiment of        the disclosure, when N is 1, only the first resource is        allocated, and both T1 and T2 may have a value of 0. In this        case, even when N is 1, the following equation may be used.

When N is greater than 1, r may be determined by Equation 6 below.

if T₂≤└W/2┘ then

r=W×T ₂ ×T ₁

else

r=W(W−T ₂)+(W−T ₁)+1  Equation 6

In the above equation, N is the number of resources assigned by the SCI,and may be N=2 or N=3. In the above, W may be a value related to a timerange in which a resource may be selected as described above. Forexample, W may be the number of a time range in which a resource can beselected, a value less than by 1, or a value greater than by 1. └x┘ maybe a value that is rounded down from x, or may indicate a maximuminteger less than or equal to x. In the above, T1 and T2 indicate timeslot information of the second and third resources, respectively, andmay be slot offsets from the first resource or the second resource. Forexample, T1 is a time offset from the first resource, and T2 is a timeoffset from the second resource. In this case, T0 may mean T0=0 as thefirst resource. T1 may have a value greater than or equal to 1, and T2may have a value greater than or equal to 0. When T2 is 0, it mayindicate that the third resource is not allocated. In other words, whenN=2, T2 may have a value of 0, and when N=3, both T1 and T2 may beintegers greater than 0 In other words, when N=3, both T1 and T2 may beintegers greater than or equal to 1. The size of the bitfield applied inthis method may be determined by

$\left\lceil {\log_{2}\left( {\sum_{i = 0}^{N_{\max} - 1}\begin{pmatrix}W \\i\end{pmatrix}} \right)} \right\rceil \mspace{14mu} {{bits}.}$

In the above, ┌x┐ may be a value rounded up from x, or may indicate aminimum integer greater than or equal to x. In order to assignresources, the transmitter may transmit the r value after assigning theresource according to the method, and the receiver may check theassigned resource after receiving r by the method.

-   -   Time resource assignment method 5: In this method, another        example is provided when Nmax=3 is configured. One bitfield is        used for time resource assignment, and T1 and T2 may be        interpreted by the bitfield value. When the bitfield value is r,        r may be determined as T1 and T2 as shown in Table 3 below.

TABLE 3 T1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 T2 0 X XX X X X X X X X X X X X X X X X X X X 1 496 X X X X X X X X X X X X X XX X X X X X 2 495 495 X X X X X X X X X X X X X X X X X X X 3 494 494494 X X X X X X X X X X X X X X X X X X 4 493 493 493 493 X X X X X X XX X X X X X X X X X 5 492 492 492 492 492 X X X X X X X X X X X X X X XX 6 491 491 491 491 491 491 X X X X X X X X X X X X X X X 7 490 490 490490 490 490 490 X X X X X X X X X X X X X X 8 489 489 489 489 489 489489 489 X X X X X X X X X X X X X 9 488 488 488 488 488 488 488 488 488X X X X X X X X X X X X 10 487 487 487 487 487 487 487 487 487 487 X X XX X X X X X X X 11 486 486 486 486 486 486 486 486 486 486 486 X X X X XX X X X X 12 485 485 485 485 485 485 485 485 485 485 485 485 X X X X X XX X X 13 484 484 484 484 484 484 484 484 484 484 484 484 484 X X X X X XX X 14 483 483 483 483 483 483 483 483 483 483 483 483 483 483 X X X X XX X 15 482 482 482 482 482 482 482 482 482 482 482 482 482 482 482 X X XX X X 16 481 481 481 481 481 481 481 481 481 481 481 481 481 481 481 481X X X X X 17 480 480 480 480 480 480 480 480 480 480 480 480 480 480 480480 480 X X X X 18 479 479 479 479 479 479 479 479 479 479 479 479 479479 479 479 479 479 X X X 19 478 478 478 478 478 478 478 478 478 478 478478 478 478 478 478 478 478 478 X X 20 477 477 477 477 477 477 477 477477 477 477 477 477 477 477 477 477 477 477 477 X 21 476 476 476 476 476476 476 476 476 476 476 476 476 476 476 476 476 476 476 476 476 22 475475 475 475 475 475 475 475 475 475 475 475 475 475 475 475 475 475 475475 475 23 474 474 474 474 474 474 474 474 474 474 474 474 474 474 474474 474 474 474 474 474 24 473 473 473 473 473 473 473 473 473 473 473473 473 473 473 473 473 473 473 473 473 25 472 472 472 472 472 472 472472 472 472 472 472 472 472 472 472 472 472 472 472 472 26 471 471 471471 471 471 471 471 471 471 471 471 471 471 471 471 471 471 471 471 47127 470 470 470 470 470 470 470 470 470 470 470 470 470 470 470 470 470470 470 470 470 28 469 469 469 469 469 469 469 469 469 469 469 469 469469 469 469 469 469 469 469 469 29 468 468 468 468 468 468 468 468 468468 468 468 468 468 468 468 468 468 468 468 468 30 467 467 467 467 467467 467 467 467 467 467 467 467 467 467 467 467 467 467 467 467 31 466466 466 466 466 466 466 466 466 466 466 466 466 466 466 466 466 466 466466 466 T1 21 22 23 24 25 26 27 28 29 30 31 T2 0 X X X X X X X X X X X 1X X X X X X X X X X X 2 X X X X X X X X X X X 3 X X X X X X X X X X X 4X X X X X X X X X X X 5 X X X X X X X X X X X 6 X X X X X X X X X X X 7X X X X X X X X X X X 8 X X X X X X X X X X X 9 X X X X X X X X X X X 10X X X X X X X X X X X 11 X X X X X X X X X X X 12 X X X X X X X X X X X13 X X X X X X X X X X X 14 X X X X X X X X X X X 15 X X X X X X X X X XX 16 X X X X X X X X X X X 17 X X X X X X X X X X X 18 X X X X X X X X XX X 19 X X X X X X X X X X X 20 X X X X X X X X X X X 21 X X X X X X X XX X X 22 475 X X X X X X X X X X 23 474 474 X X X X X X X X X 24 473 473473 X X X X X X X X 25 472 472 472 472 X X X X X X X 26 471 471 471 471471 X X X X X X 27 470 470 470 470 470 470 X X X X X 28 469 469 469 469469 469 469 X X X X 29 468 468 468 468 468 468 468 468 X X X 30 467 467467 467 467 467 467 467 467 X X 31 466 466 466 466 466 466 466 466 466 1X

In the above Table 3, T1 refers to the time slot of the i-th resource,and in the disclosure, T0 refers to T0=0 as the first resource, whenT1>0, T1 and T2 refer to the time slot information of the second andthird resource, respectively, and when T1=0, T2 refers to the time slotinformation of the second resource, and is a slot offset from the firstresource.

As an example, consider the case where W=32 and Nmax=3. In this case,

$\left\lceil {\log_{2}\left( {\sum_{i = 0}^{2}\begin{pmatrix}31 \\i\end{pmatrix}} \right)} \right\rceil = 9$

bits are needed to apply this method.

Second Embodiment

The second embodiment provides a method and an apparatus for applying alocation at which a demodulation reference signal (DMRS) for datatransmission, that is, PSSCH transmission, is transmitted/received insidelink communication.

In a wireless communication system, it may be necessary to amplify thestrength of signals while the terminal receives the signal. To this end,signal processing is performed after the received signal is passedthrough an amplifier to amplify the intensity of the signal, and anamplifier capable of varying the degree of amplification of the signalmay be used. Each amplifier may have a range of inputs or outputs havinglinearity between the inputs and outputs. If the amplification isperformed by increasing the amplification degree too high, the outputmay be determined in a range outside the linearity, and thus thereceived signal may be deformed, and this deformation may deterioratethe reception performance. Therefore, in order to guarantee theperformance, the degree of amplification should be operated in a periodhaving linearity between the input and output of the amplifier. Inaddition, if the degree of amplification is set too low, the receptionperformance might not be secured because the amplification of thereceived signal is not sufficiently amplified. Therefore, the degree ofamplification can be continuously adjusted automatically so as toamplify as much as possible in a section with linearity between theinput and output of the amplifier, this is called automatic gain control(AGC). The terminal can perform AGC to find an appropriate degree ofamplification, and it takes some time to find the appropriate degree ofamplification, and this required time is referred to as AGC trainingtime. The signal received during the AGC training time may not be usedfor actual control and data signal reception, and the AGC training timemay be determined according to an initial value configuring of anamplification degree for performing AGC. In sidelink communication inwhich a terminal to which a signal is transmitted may changecontinuously, the receiving terminal should continuously perform theAGC, and thus an AGC training time may be required for each signalreception. As described above, as the AGC training time required for thereceiving terminal is reduced, the interval of the received signal thatthe terminal can use for signal processing increases, so that receptionperformance can be improved.

The transmitting terminal may transmit the preamble signal in one ormore symbols before transmitting the sidelink control channel and data.The preamble signal may be used to enable the receiving terminal tocorrectly perform automatic gain control (AGC) for adjusting theintensity of amplification when amplifying the power of the receivedsignal. A PSCCH including control information is transmitted in initialsymbols of a slot, and a PSSCH scheduled by the control information ofthe PSCCH may be transmitted. A part of SCI, which is controlinformation, may be mapped to the PSSCH and transmitted. A preamblesignal for performing AGC may be separately transmitted in the physicalchannel structure in the sidelink slot, but the sidelink channel andsignal to be transmitted in the second symbol may be copied andtransmitted in the first symbol, and the receiving terminal may performAGC using this.

FIGS. 10A, 10B, 10C, and 10D are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure. FIGS. 10A and 10B are diagrams illustrating positions ofsymbols including DMRSs when one symbol is used for DMRS transmitted inone slot in sidelink transmission/reception. Referring to FIG. 10A, itillustrates an example when a control channel (PSCCH) is transmitted inthree symbols, and FIG. Referring to 10B, it illustrates an example whena PSCCH is transmitted in two symbols. According to the embodiment ofFIGS. 10A and 10B, the DMRS symbol position is determined irrespectiveof the number of symbols in which the PSCCH is transmitted, and thus canhave an advantage of being easy for terminal implementation. A symbolfor performing AGC required for sidelink reception may be transmitted inthe first symbol, and transmission in this symbol may be irrelevant tothe DMRS. For example, it is not necessary to decode the signaltransmitted in the first symbol using DMRS. Therefore, DMRS may bemodified or delayed compared to the NR system of the related art. Inaddition, the DMRS symbol is not located in the first symbol, because ifAGC is performed in the first symbol, it might not be well utilized forchannel estimation for demodulation and decoding.

FIG. 10C is a diagram illustrating a case where a PSCCH is transmittedin two symbols. Referring to FIG. 10C, the DMRS has a structure in whichthe DMRS can be transmitted immediately after the PSSCH, and this may beto enable channel estimation to be performed as quickly as possible.

In sidelink transmission/reception, it may be applied totransmission/reception between terminals including at least one of theDMRS symbol positions illustrated in FIGS. 10A, 10B, and 10C.

In sidelink transmission/reception, a part of the pattern provided inFIG. 10A, a part of the pattern provided in FIG. 10B, or a part of thepattern provided in FIG. 10C may be applied or combined to be applied totransmission/reception between terminals according to configuration. Inthe above, the pattern may refer to the position of the DMRS in theslot.

The positions of the symbols in which the DMRS is transmitted describedin this embodiment may be changed and applied to other possiblepositions according to the subcarrier spacing of the resource on whichsidelink transmission is performed.

In addition, the positions of the symbols in which the DMRS istransmitted described in this embodiment may be applied by combiningpatterns of different positions according to the assigned length of thePSSCH. In the above, the assigned length of the PSSCH may be the numberof symbols used for PSSCH transmission including DMRS excluding AGCsymbols.

In addition, in the method provided in this embodiment of thedisclosure, a PSSCH may be mapped to a DMRS symbol according toavailability of the resources.

In addition, in the method provided in this embodiment of thedisclosure, a part of control information may be mapped to a DMRS symbolaccording to the availability of the resources or resources of thePSSCH.

The DMRS pattern provided in this embodiment may be a physicallyabsolute symbol position within a slot, but may be a relative symbolposition according to an applied example. For example, the position ofthe DMRS symbol may be changed according to the positions of symbolsused for the sidelink within the slot. For example, when p is the indexof the first symbol of the PSCCH, the position of the DMRS symbolprovided in the embodiment may be given as a relative offset value fromp. Referring to FIG. 10D, it illustrates an embodiment in which a partof FIG. 10A is applied when the first three symbols in a slot are usedfor downlink. FIGS. 11A, 11B, and 11C are diagrams illustrating a methodof determining a DMRS time resource according to various embodiments ofthe disclosure.

FIGS. 11A and 11B are diagrams illustrating positions of symbolsincluding DMRSs when DMRSs transmitted in one slot are transmitted intwo symbols in sidelink transmission/reception. Referring to FIG. 11A,it illustrates an example when a control channel (PSCCH) is transmittedin three symbols, and referring to FIG. 11B, it illustrates shows anexample when a PSCCH is transmitted in two symbols. According to theembodiments of FIGS. 11A and 11B, the DMRS symbol position is determinedirrespective of the number of symbols in which the PSCCH is transmitted,and thus can have an advantage of being easy for terminalimplementation. A symbol for performing AGC required for sidelinkreception may be transmitted in the first symbol, and transmission inthis symbol may be irrelevant to the DMRS. For example, it is notnecessary to decode the signal transmitted in the first symbol usingDMRS. Therefore, DMRS may be modified or delayed compared to the NRsystem of the related art. In addition, the DMRS symbol is not locatedin the first symbol, because if AGC is performed in the first symbol, itmight not be well utilized for channel estimation for demodulation anddecoding.

Referring to FIG. 11C, it is a diagram illustrating a case where a PSCCHis transmitted in two symbols. In FIG. 11C, the DMRS has a structure inwhich the DMRS can be transmitted immediately after the PSSCH, and thismay be to enable channel estimation to be performed as quickly aspossible.

In sidelink transmission/reception, it may be applied totransmission/reception between terminals including at least one of theDMRS symbol positions shown in FIGS. 11A, 11B, and 11C.

In sidelink transmission/reception, a part of the pattern provided inFIG. 11A, a part of the pattern provided in FIG. 11B, or a part of thepattern provided in FIG. 11C may be applied or combined to be applied totransmission/reception between terminals according to a configuration.In the above, the pattern may refer to the position of the DMRS in theslot.

FIGS. 12A, 12B, 12C, and 12D are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure.

Referring to FIGS. 12A, 12B, 12C, and 12D, they are diagramsillustrating positions of symbols including DMRSs when DMRSs transmittedin one slot are transmitted in three symbols in sidelinktransmission/reception. FIGS. 12A and 12C illustrate a control channel(PSCCH) being transmitted in three symbols, and FIGS. 12B and 12Dillustrate when a PSCCH being transmitted in two symbols. When FIGS. 12Aand 12B are used together, or when FIGS. 12C and 12D are used together,the position of the DMRS symbol is determined regardless of the numberof symbols to which the PSCCH is transmitted, and thus, it may have anadvantage of being easy for terminal implementation. A symbol forperforming AGC required for sidelink reception may be transmitted in thefirst symbol, and transmission in this symbol may be irrelevant to theDMRS. For example, it is not necessary to decode the signal transmittedin the first symbol using DMRS. Therefore, DMRS can be modified ordelayed compared to the NR system of the related art. In addition, theDMRS symbol is not located in the first symbol, because if AGC isperformed in the first symbol, it might not be well utilized for channelestimation for demodulation and decoding.

In sidelink transmission/reception, it may be applied totransmission/reception between terminals including at least one of theDMRS symbol positions shown in FIGS. 12A, 12B, 12C, and 12D.

In sidelink transmission/reception, a part of the pattern provided inFIG. 12A, a part of the pattern provided in FIG. 12B, or a part of thepattern provided in FIG. 12C, or a part of the pattern provided in FIG.12D may be applied or combined to be applied to transmission/receptionbetween terminals according to configurations. In the above, the patternmay refer to the position of the DMRS in the slot.

FIGS. 13A, 13B, 13C, 13D, 13E, 13F, and 13G are diagrams illustrating amethod of determining DMRS time resources according to variousembodiments of the disclosure.

Referring to FIGS. 13A, 13B, 13C, and 13D, they are diagramsillustrating positions of symbols including DMRS when DMRS transmittedin one slot is transmitted in four symbols in sidelinktransmission/reception. FIGS. 13A and 13C illustrate a control channel(PSCCH) being transmitted in three symbols, and FIGS. 13B and 13Dillustrate when a PSCCH being transmitted in two symbols. When FIG. 13Aand FIG. 13B are used together, or when FIG. 13C and FIG. 13D are usedtogether, the position of the DMRS symbol may be determined irrespectiveof the number of symbols to which the PSCCH is transmitted, and thus canhave an advantage of being easy for terminal implementation. A symbolfor performing AGC required for sidelink reception may be transmitted inthe first symbol, and transmission in this symbol may be irrelevant tothe DMRS. For example, it is not necessary to decode the signaltransmitted in the first symbol using DMRS. Therefore, DMRS can bemodified or delayed compared to the NR system of the related art. Inaddition, the DMRS symbol is not located in the first symbol, because ifAGC is performed in the first symbol, it might not be well utilized forchannel estimation for demodulation and decoding.

In sidelink transmission/reception, it may be applied totransmission/reception between terminals including at least one of theDMRS symbol positions shown in FIGS. 13A, 13B, 13C, and 13D.

In sidelink transmission and reception, a part of the pattern providedin FIG. 13A, a part of the pattern provided in FIG. 13B, a part of thepattern provided in FIG. 13C, or a part of the pattern provided in FIG.13D may be applied or combined to be applied to transmission/receptionbetween terminals according to configurations. In the above, the patternmay refer to the position of the DMRS in the slot.

In the above, FIGS. 13C and 13D may illustrate a scheme in which therelative position of the downlink DMRS symbol is maximally reused in theNR system of the related art. Specifically, for example, part (a) ofFIG. 13E illustrates DMRS being transmitted in 1, 2, 3, or 4 symbols,based on a method of reusing the relative position of a downlink DMRSsymbol in an NR system. Part (b) of FIG. 13E illustrates DMRS beingtransmitted in 1, 2, 3, or 4 symbols, based on a method of reusing therelative position of the downlink DMRS symbol as much as possible in theNR system. Part (b) of FIG. 13E may illustrates a method of increasingthe decoding performance of the PSSCH by increasing the position of thefirst DMRS symbol by one compared to part (a) of FIG. 13E. Of course,the DMRS location provided in parts (a) or (b) of FIG. 13E may beapplied in combination with the DMRS location provided above.

Referring to FIG. 13E, it may be modified and applied as shown in FIG.13F or 13G.

Third Embodiment

The third embodiment provides another example of a method and anapparatus for transmitting a DMRS in sidelink data transmissionincluding communication between terminals.

FIGS. 14A, 14B, 14C, 14D, and 14E are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure.

In this embodiment of the disclosure, another example in which therelative position of a downlink DMRS symbol, that is, a DMRS symbol of aPDSCH, is reused as much as possible in an NR system of the related artis provided. In addition, the embodiment provides another example inwhich the relative position of an uplink DMRS symbol, that is, a DMRSsymbol of a PUSCH, is maximally reused in an NR system of the relatedart. The DMRS symbol of the PUSCH mentioned above may vary according tothe PUSCH type of the NR system. In the case of PUSCH type A, theposition of the DMRS symbol is the same as the position of the DMRSsymbol of the PDSCH, which is a downlink, and in the case of PUSCH typeB, the position of the DMRS symbol is different from the position of theDMRS symbol of the PDSCH, which is a downlink.

If the positions in the slots of the DMRS of the PDSCH and the DMRS ofthe PUSCH type A defined in the NR system of the related art areregarded as relative positions from the first symbol of the PSCCH, whichis a control channel transmitted in the slot of the sidelink, thepositions may be applied as in FIGS. 14B, 14C, 14D, and 14E.

Referring to FIGS. 14B, 14C, 14D, and 14E, they are diagramsillustrating patterns including 1, 2, 3, and 4 DMRS symbols,respectively, and each may be patterns used according to parametervalues, such as dmrs_number or dmrs-AdditionalPosition, the number ofsymbols used for PSSCH mapping, and the number of symbols used forPSCCH. For example, when dmrs-AdditionalPosition=pos2 (here, indmrs-AdditionalPosition, it may refer to the number of additionalsymbols other than 1, and for example, pos2 may refer to a total of 3DMRS symbols, that is, posX may be a parameter value that refers to atotal of X+1 symbols), one of the illustrated DMRS patterns may beselected and used according to the number of PSSCH symbols and thenumber of PSCCH symbols among the DMRS patterns illustrated in FIG. 14D.

FIGS. 14B, 14C, 14D, and 14E illustrate patterns in which the locationof the first DMRS that appears can be changed according to the number ofPSCCH symbols, and the number of PSCCH symbols may be configured in aresource pool or may be determined by a preset value.

In the diagrams described in this embodiment of the disclosure, diagramsshowing what purpose a total of 14 OFDM symbols are used, and asillustrated in FIG. 14A, an OFDM symbol index and a frequency resourceare assumed.

FIGS. 15A, 15B, 15C, and 15D are diagrams illustrating a method ofdetermining DMRS time resources according to various embodiments of thedisclosure.

According to an embodiment of the disclosure, if the positions in theslot of the DMRS of PUSCH type B defined in an NR system are regarded asrelative positions from the first symbol of the PSCCH, which is acontrol channel transmitted in the slot of the sidelink, the positionsmay be applied as in FIGS. 15A, 15B, 15C, and 15D.

Referring to FIGS. 15A, 15B, 15C, and 15D, they are diagramsillustrating patterns including 1, 2, 3, and 4 DMRS symbols,respectively, and each may be patterns used according to parametervalues, such as dmrs_number or dmrs-AdditionalPosition and the number ofsymbols used for PSSCH mapping. For example, for example, whendmrs-AdditionalPosition=pos2 (here, dmrs-AdditionalPosition may refer tothe number of additional symbols other than 1, and for example, pos2 mayrefer to a total of 3 DMRS symbols, that is, posX may be a parametervalue that means a total of X+1 symbols), one of the illustrated DMRSpatterns may be selected and used according to the number of PSSCHsymbols among the DMRS patterns illustrated in FIG. 15D.

In the disclosure, the position of the first symbol of the PSCCH, whichis the control channel transmitted in the slot of the sidelink, mayrefer to the second symbol used as the sidelink in the slot.

In the disclosure, the parameter value, such as dmrs_number ordmrs-AdditionalPosition may be a value transmitted from controlinformation (SCI) or first control information (1st stage SCI).Alternatively, the parameter value, such as dmrs_number ordmrs-AdditionalPosition may be a value configured in the resource pool,or may be a value indicated by SCI among values configured in theresource pool. For example, a 2-bit indicator is transmitted in SCI, andthe 2-bit indicator may indicate a value of dmrs-AdditionalPosition.

FIG. 16 is a diagram illustrating a method of determining DMRS timeresources according to an embodiment of the disclosure.

Referring to FIG. 16A, according to an embodiment of the disclosure, atleast one of the patterns of FIGS. 14B to 14E and 15A to 15D may becombined with each other to be supported in the sidelink. For example,the DMRS pattern including one symbol DMRS in the sidelink may use thepattern of FIG. 14B. This is because the pattern of FIG. 15A does notinclude the DMRS in some frequency domains, so data decoding performancemay deteriorate. In addition, for example, a DMRS pattern including twosymbol DMRSs in the sidelink may be used in combination with FIGS. 14Cand 15B, and in the pattern shown in FIG. 14C, only one DMRS symbol issupported in a short-length PSSCH. The pattern according to thisembodiment may be as shown in FIG. 16. In addition to the patterns ofFIG. 16, for example, a DMRS pattern including 3 symbol DMRSs in thesidelink may use FIG. 15C, and a DMRS pattern including 4 symbol DMRSsin the sidelink may use FIG. 15D.

According to examples provided in this embodiment of the disclosure, inFIGS. 14B, 14C, 14D, 14E, 15A, 15B, 15C, 15E, and 16, some or acombination of some of the patterns provided according to the length ofthe PSSCH and the length of the PSCCH may be used.

Other possible positions may be applied according to subcarrier spacingas the position of the symbol in which the DMRS is transmitted describedin this embodiment. In the examples of FIGS. 14B, 14C, 14D, 14E, 15A,15B, 15C, 15E, and 16 provided in this embodiment of the disclosure,some or a combinations of some of the patterns provided according to thelength of the PSSCH and the length of the PSCCH may be used differentlyaccording to the subcarrier spacings.

The position of the symbol in which the DMRS is transmitted described inthis embodiment may be applied by combining patterns of differentpositions according to the assigned length of the PSSCH. In the above,the assigned length of the PSSCH may be the number of symbols used forPSSCH transmission including DMRS excluding AGC symbols.

In addition, in the method provided in this embodiment of thedisclosure, a PSSCH may be mapped to a DMRS symbol according toavailability of available resources.

In addition, in the method provided in this embodiment of thedisclosure, a part of control information may be mapped to the DMRSsymbol according to the availability of available resources or resourcesof the PSSCH.

The DMRS pattern provided in this embodiment may be a physicallyabsolute symbol position within a slot, but may be a relative symbolposition according to an applied embodiment. For example, the positionof the DMRS symbol may be changed according to the positions of symbolsused for the sidelink within the slot. For example when p is the indexof the first symbol of the PSCCH, the position of the DMRS symbolprovided in this embodiment may be given as a relative offset value fromp. As an example, when the first three symbols in a slot are used fordownlink, an embodiment in which a part of FIG. 16 is applied may beimplemented as in the pattern of FIG. 10D.

Transmitters, receivers, and processors of the terminal and the basestation to carry out the above embodiments are shown in FIGS. 17 and 18,respectively. In order to perform sidelink-related operations proposedthrough the first to third embodiments of the disclosure, the receivers,the processors, and the transmitters of the base station and theterminal must operate according to the respective embodiments.

FIG. 17 is a block diagram illustrating an internal structure of aterminal according to an embodiment of the disclosure.

Referring to FIG. 17, the terminal of the disclosure may include aterminal receiver 1700, a terminal transmitter 1704, and a terminalprocessor 1702. The terminal receiver 1700 and the terminal transmitter1704 may be collectively referred to as a transceiver in an embodiment.The transceiver may transmit and receive signals with the base station.The signal may include control information and data. To this end, thetransceiver may include an RF transmitter that up-converts and amplifiesa frequency of a transmitted signal, and an RF receiver that amplifies areceived signal with low noise and down-converts a frequency. Inaddition, the transceiver may receive a signal through a wirelesschannel, output the same to the terminal processor 1702, and transmit asignal output from the terminal processor 1702 through the wirelesschannel. The terminal processor 1702 may control a series of processesso that the terminal can operate according to the embodiment describedabove.

FIG. 18 is a block diagram illustrating an internal structure of a basestation according to an embodiment of the disclosure.

Referring to FIG. 18, the base station may include a base stationreceiver 1801, a base station transmitter 1805, and a base stationprocessor 1803. The base station receiver 1801 and the base stationtransmitter 1805 may be collectively referred to as a transceiver in anembodiment. The transceiver may transmit and receive signals with theterminal. The signal may include control information and data. To thisend, the transceiver may include an RF transmitter that up-converts andamplifies a frequency of a transmitted signal, and an RF receiver thatamplifies a received signal with low noise and down-converts afrequency. In addition, the transceiver may receive a signal through awireless channel, output it to the base station processing unit 1803,and transmit the signal output from the base station processor 1803through the wireless channel. The base station processor 1803 maycontrol a series of processes so that the base station can operateaccording to the above-described embodiment.

While the disclosure has been shown and described with reference tovarious embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims and their equivalents.

What is claimed is:
 1. A method performed by a first terminal in awireless communication system, the method comprising: identifying anumber of symbols for physical sidelink shared channel (PSSCH)transmission and a number of symbols for PSSCH demodulation referencesignal (DMRS); transmitting, to a second terminal, sidelink controlinformation (SCI) for scheduling the PSSCH transmission, the SCIincluding DMRS pattern information identified based on the number ofsymbols for the PSSCH DMRS; and transmitting, to the second terminal,the PSSCH DMRS at a position identified based on the SCI, wherein asymbol index of the position at which the PSSCH DMRS is transmitted isidentified by one of a plurality of index groups included in a firstindex group for the number of symbols of the PSSCH DMRS being 2, asecond index group for the number of symbols of the PSSCH DMRS being 3,and a third index group for the number of symbols of the PSSCH DMRSbeing 4, and wherein the first index group includes {1, 5}, {3, 8}, {3,10}, {4, 8}, and {4, 10}, the second index group includes {1, 4, 7}, {1,5, 9}, and {1, 6, 11}, and the third index group includes {1, 4, 7, 10}.2. The method of claim 1, wherein, in case that the number of symbolsfor the PSSCH transmission is 7 or 8, {1, 5} included in the first indexgroup is applied.
 3. The method of claim 1, wherein, in case that thenumber of symbols for the PSSCH transmission is 9 or 10, and the numberof symbols for a physical sidelink control channel (PSCCH) through whichthe SCI is transmitted is 2, {3, 8} included in the first index group isapplied, and wherein, in case that the number of symbols for the PSSCHtransmission is 9 or 10, and the number of symbols for the PSCCH throughwhich the SCI is transmitted is 3, {4, 8} included in the first indexgroup is applied.
 4. The method of claim 1, wherein, in case that thenumber of symbols for the PSSCH transmission is 11, 12 or 13, and thenumber of symbols for the PSCCH through which the SCI is transmitted is2, {3, 10} included in the first index group is applied, and wherein, incase that the number of symbols for the PSSCH transmission is 11, 12, or13 and the number of symbols for the PSCCH through which the SCI istransmitted is 3, {4, 10} included in the first index group is applied.5. The method of claim 1, wherein, in case that the number of symbolsfor the PSSCH transmission is 9 or 10, {1, 4, 7} included in the secondindex group is applied, wherein, in case that the number of symbols forthe PSSCH transmission is 11 or 12, {1, 5, 9} included in the secondindex group is applied, and wherein, in case that the number of symbolsfor the PSSCH transmission is 13, {1, 6, 11} included in the secondindex group is applied.
 6. A method performed by a second terminal in awireless communication system, the method comprising: receiving, from afirst terminal, sidelink control information (SCI) for scheduling aphysical sidelink shared channel (PSSCH) transmission, the SCI includingdemodulation reference signal (DMRS) pattern information identifiedbased on a number of symbols for a PSSCH DMRS; identifying a number ofsymbols for the PSSCH transmission and the number of symbols for thePSSCH DMRS, based on the SCI; and receiving, from the first terminal,the PSSCH DMRS at a position identified based on the SCI, wherein asymbol index of the position at which the PSSCH DMRS is received isidentified by one of a plurality of index groups included in a firstindex group for the number of symbols of the PSSCH DMRS being 2, asecond index group for the number of symbols of the PSSCH DMRS being 3,and a third index group for the number of symbols of the PSSCH DMRSbeing 4, and wherein the first index group includes {1, 5}, {3, 8}, {3,10}, {4, 8}, and {4, 10}, the second index group includes {1, 4, 7}, {1,5, 9}, and {1, 6, 11}, and the third index group includes {1, 4, 7, 10}.7. The method of claim 6, wherein, in case that the number of symbolsfor the PSSCH transmission is 7 or 8, {1, 5} included in the first indexgroup is applied.
 8. The method of claim 6, wherein, in case that thenumber of symbols for the PSSCH transmission is 9 or 10, and the numberof symbols for a physical sidelink control channel (PSCCH) through whichthe SCI is transmitted is 2, {3, 8} included in the first index group isapplied, and wherein, in case that the number of symbols for the PSSCHtransmission is 9 or 10, and the number of symbols for the PSCCH throughwhich the SCI is transmitted is 3, {4, 8} included in the first indexgroup is applied.
 9. The method of claim 6, wherein, in case that thenumber of symbols for the PSSCH transmission is 11, 12 or 13, and thenumber of symbols for the PSCCH through which the SCI is transmitted is2, {3, 10} included in the first index group is applied, and wherein, incase that the number of symbols for the PSSCH transmission is 11, 12, or13 and the number of symbols for the PSCCH through which the SCI istransmitted is 3, {4, 10} included in the first index group is applied.10. The method of claim 6, wherein, in case that the number of symbolsfor the PSSCH transmission is 9 or 10, {1, 4, 7} included in the secondindex group is applied, wherein, in case that the number of symbols forthe PSSCH transmission is 11 or 12, {1, 5, 9} included in the secondindex group is applied, and wherein, in case that the number of symbolsfor the PSSCH transmission is 13, {1, 6, 11} included in the secondindex group is applied.
 11. A first terminal in a wireless communicationsystem, the first terminal comprising: a transceiver configured totransmit and receive a signal; and at least one processor coupled to thetransceiver, wherein the at least one processor is configured to:identify a number of symbols for physical sidelink shared channel(PSSCH) transmission and a number of symbols for PSSCH demodulationreference signal (DMRS), transmit, to a second terminal, sidelinkcontrol information (SCI) for scheduling the PSSCH transmission, the SCIincluding DMRS pattern information identified based on the number ofsymbols for the PSSCH DMRS, and transmit, to the second terminal, thePSSCH DMRS at a position identified based on the SCI, wherein a symbolindex of the position at which the PSSCH DMRS is transmitted isidentified by one of a plurality of index groups included in a firstindex group for the number of symbols of the PSSCH DMRS being 2, asecond index group for the number of symbols of the PSSCH DMRS being 3,and a third index group for the number of symbols of the PSSCH DMRSbeing 4, and wherein the first index group includes {1, 5}, {3, 8}, {3,10}, {4, 8}, and {4, 10}, the second index group includes {1, 4, 7}, {1,5, 9}, and {1, 6, 11}, and the third index group includes {1, 4, 7, 10}.12. The first terminal of claim 11, wherein, in case that the number ofsymbols for the PSSCH transmission is 7 or 8, {1, 5} included in thefirst index group is applied.
 13. The first terminal of claim 11,wherein, in case that the number of symbols for the PSSCH transmissionis 9 or 10, and the number of symbols for a physical sidelink controlchannel (PSCCH) through which the SCI is transmitted is 2, {3, 8}included in the first index group is applied, and wherein, in case thatthe number of symbols for the PSSCH transmission is 9 or 10, and thenumber of symbols for the PSCCH through which the SCI is transmitted is3, {4, 8} included in the first index group is applied.
 14. The firstterminal of claim 11, wherein, in case that the number of symbols forthe PSSCH transmission is 11, 12 or 13, and the number of symbols forthe PSCCH through which the SCI is transmitted is 2, {3, 10} included inthe first index group is applied, and wherein, in case that the numberof symbols for the PSSCH transmission is 11, 12, or 13 and the number ofsymbols for the PSCCH through which the SCI is transmitted is 3, {4, 10}included in the first index group is applied.
 15. The first terminal ofclaim 11, wherein, in case that the number of symbols for the PSSCHtransmission is 9 or 10, {1, 4, 7} included in the second index group isapplied, wherein, in case that the number of symbols for the PSSCHtransmission is 11 or 12, {1, 5, 9} included in the second index groupis applied, and wherein, in case that the number of symbols for thePSSCH transmission is 13, {1, 6, 11} included in the second index groupis applied.
 16. A second terminal in a wireless communication system,the second terminal comprising: a transceiver configured to transmit andreceive a signal; and at least one processor coupled to the transceiver,wherein the at least one processor is configured to: receive, from afirst terminal, sidelink control information (SCI) for scheduling aphysical sidelink shared channel (PSSCH) transmission, the SCI includingdemodulation reference signal (DMRS) pattern information identifiedbased on a number of symbols for a PSSCH DMRS, identify a number ofsymbols for the PSSCH transmission and the number of symbols for thePSSCH DMRS, based on the SCI, and receive, from the first terminal, thePSSCH DMRS at a position identified based on the SCI, wherein a symbolindex of the position at which the PSSCH DMRS is received is identifiedby one of a plurality of index groups included in a first index groupfor the number of symbols of the PSSCH DMRS being 2, a second indexgroup for the number of symbols of the PSSCH DMRS being 3, and a thirdindex group for the number of symbols of the PSSCH DMRS being 4, andwherein the first index group includes {1, 5}, {3, 8}, {3, 10}, {4, 8},and {4, 10}, the second index group includes {1, 4, 7}, {1, 5, 9}, and{1, 6, 11}, and the third index group includes {1, 4, 7, 10}.
 17. Thesecond terminal of claim 16, wherein, in case that the number of symbolsfor the PSSCH transmission is 7 or 8, {1, 5} included in the first indexgroup is applied.
 18. The second terminal of claim 16, wherein, in casethat the number of symbols for the PSSCH transmission is 9 or 10, andthe number of symbols for a physical sidelink control channel (PSCCH)through which the SCI is transmitted is 2, {3, 8} included in the firstindex group is applied, and wherein, in case that the number of symbolsfor the PSSCH transmission is 9 or 10, and the number of symbols for thePSCCH through which the SCI is transmitted is 3, {4, 8} included in thefirst index group is applied.
 19. The second terminal of claim 16,wherein, in case that the number of symbols for the PSSCH transmissionis 11, 12 or 13, and the number of symbols for the PSCCH through whichthe SCI is transmitted is 2, {3, 10} included in the first index groupis applied, and wherein, in case that the number of symbols for thePSSCH transmission is 11, 12, or 13 and the number of symbols for thePSCCH through which the SCI is transmitted is 3, {4, 10} included in thefirst index group is applied.
 20. The second terminal of claim 16,wherein, in case that the number of symbols for the PSSCH transmissionis 9 or 10, {1, 4, 7} included in the second index group is applied,wherein, in case that the number of symbols for the PSSCH transmissionis 11 or 12, {1, 5, 9} included in the second index group is applied,and wherein, in case that the number of symbols for the PSSCHtransmission is 13, {1, 6, 11} included in the second index group isapplied.